Computer tomography apparatus

ABSTRACT

The invention relates to a computer tomography apparatus for examining a body part of a large animal, comprising a computer tomography (CT) device and a platform on which the CT device is mounted. The CT device has an annular gantry and a CT table to accommodate a body part of a large animal to be examined. The gantry is immovable relative to the platform. Relative to the platform and to the gantry the CT table is horizontally movably connected to the gantry and/or the platform in such a way that the CT table can be moved into a central opening in the annular gantry. The computer tomography apparatus further comprises a positioning device which is connected to the platform and is designed to position the platform having the mounted CT device relative to a supporting surface for a large animal. The positioning device is designed to position the platform having the mounted CT device in an operational state in such a way that during a relative movement with respect to the gantry the CT table remains stationary relative to the supporting surface.

The invention relates to a computer tomography apparatus for examining a body part of a large animal, and to a method of examining a body part of a large animal by means of a computer tomography apparatus.

A computer tomography (CT) device will typically have a gantry designed as an annular tunnel and a CT table which can be moved into the central opening in the annular gantry and onto which a patient or an examination subject can be placed. In the gantry, a CT tube and, opposite the CT tube, a detector system are eccentrically arranged and rotate in the annular tunnel while a CT scan is taking place. The CT tube emits a fan beam of X-rays in the direction of the detector system. When a patient or an examination subject on the CT table has been moved into the central opening in the annular gantry, the X-rays penetrate the area to be examined and their intensity is reduced depending on the absorption properties within the illuminated area. If structures with different absorption properties—for example bone and soft tissue—are present in the illuminated area, the X-rays in the illuminated area are reduced to different degrees. The detector detects a two-dimensional projection of the usually three-dimensional illuminated subject, whereby the projection represents an intensity map of the detected X-rays. The rotation of the CT tube and of the detector system make it possible to record a plurality of projections of a subject to be examined from different directions during the CT scan, from which a computer, performing the corresponding calculations, can reconstruct the original three-dimensional structure of the examined subject.

However, the commercially available CT device described above, is only suitable to a limited extent for performing a CT scan on a standing large animal. Often, a CT scan will only be able to be performed on a lying large animal under general anesthesia and therefore entails relatively high risks and efforts. CT devices that make it possible to perform a CT scan on a standing large animal are often restricted to the examination of certain body parts of a large animal. If, for example, a sliding gantry of a CT device is used for a CT scan, in case of a standing large animal, for example a horse, typically only the head and the neck, but, in particular, not the limbs, will be able to be examined. In case of such an arrangement of the gantry on rails, it may be necessary to lift a patient standing on a lifting platform to a specific height, in order to position a body part to be examined in the opening in the annular gantry. Lifting a large animal, such as a horse, on a lifting platform poses a significant risk to the large animal and complicates a CT scan of the large animal even further, since, for example, a large animal will regularly only be able to be lifted slowly, which means that duration of the examination will be significantly increased. Moreover, an arrangement of a gantry on rails requires significantly more space compared to the CT device described at the beginning. Thus, both versions described above have a number of disadvantages.

U.S. Pat. No. 9,301,726 B2 describes a CT machine for scanning a stationary patient, for example a human or a horse. The CT machine has two-bar linkage articulated arms to move a CT gantry in an arbitrary trajectory and thus clearly differs from the basic design of the commercially available CT device described at the beginning.

It is an object of the invention to provide an improved computer tomography apparatus for examining a body part of a stationary, standing large animal, and a method of examining a body part of a stationary, standing large animal by means of a computer tomography apparatus.

With regard to the computer tomography apparatus, the object of the invention is achieved by means of a computer tomography apparatus for examining a body part of a large animal, comprising a computer tomography (CT) device and a platform on which the CT device is mounted. The CT device has an annular gantry and a CT table to accommodate a body part of a large animal to be examined. The gantry is arranged relative to the platform on the platform.

Relative to the platform and to the gantry, the CT table is horizontally movably connected to the gantry and/or the platform in such a way that the CT table can be moved into a central opening in the annular gantry.

Pursuant to the invention, the computer tomography apparatus further comprises a positioning device which is connected to the platform and is designed to horizontally position the platform having the mounted CT device relative to a supporting surface for a large animal. The positioning device is further designed to position the platform having the mounted CT device in an operational state in such a way that during a relative movement with respect to the gantry the CT table remains stationary relative to the supporting surface.

In the context of this description, a supporting surface means a solid base that is located on the side of the gantry opposite the CT table. The supporting surface is located outside the computer tomography apparatus. During a CT scan with the computer tomography apparatus pursuant to the invention, a large animal to be examined is stationary, standing on the supporting surface.

The CT device of the computer tomography apparatus pursuant to the invention is designed in the same way as a commercially available CT device and comprises a gantry and a CT table to accommodate a body part of a large animal to be examined. For a CT scan, the CT table can be moved into the gantry, so that the projections from various directions described above, which can be processed by means of a computer, can be recorded. Thus, advantageously, no material changes compared to the commercially available CT device will have to be made to the CT device of the computer tomography apparatus pursuant to the invention.

The invention is based on the realization that it is advantageous to use a commercially available CT device, since thus the efforts of a conversion or the efforts of the development of a new CT device and the associated costs can be saved. Another advantage of a commercially available device is that the computer tomography apparatus is not limited to a specific CT device, but can be realized with a plurality of commercially available CT devices and, in particular, independently of the manufacturer.

The invention is based on the consideration that a commercially available CT device as such is not suitable for examining a body part of a stationary large animal standing on a supporting surface, since, for the scan, the body part of the large animal to be examined must be moved through the gantry on the CT table. To this end, the large animal would have to give up its stationary position on the supporting surface, in order to follow the movement of the retracting CT table. This would make a CT scan of a body part significantly harder and the large animal would be exposed to additional stress.

However, the inventors have realized that this disadvantage can be eliminated if the computer tomography apparatus comprises a platform and a positioning device connected to the platform. Thus, pursuant to the invention, the CT device is mounted on the platform. Thus, the platform serves as the supporting surface of the CT device and is designed to carry the CT device.

The positioning device is designed to position the platform horizontally relative to the supporting surface for a large animal. The supporting surface for the large animal is located outside the platform, so that a stationary, standing large animal itself does not move, when the platform with the CT device is positioned horizontally relative to the supporting surface. However, during a CT scan, the body part of the large animal to be examined is lying on the CT table and would be moved into the gantry along with the CT table. In order to prevent a horizontal positioning of the body part to be examined during a CT scan relative to the supporting surface, i.e. also relative to the rest of the large animal, it is required pursuant to the invention that the computer tomography apparatus has at least one operational state, in which the platform is positioned horizontally in such a way that during a relative movement with respect to the gantry the CT table remains stationary relative to the supporting surface.

From the point of view of an outside observer, the CT table is standing still in this operational state of the computer tomography apparatus. Thus, to the outside observer it looks as if the gantry, which is immovably mounted on the platform, is moving over the CT table and, in particular, over a body part of a large animal to be examined. In this operational state, the elements of the CT device that are moving from the point of view of the outside observer are precisely those elements that would not move in case of a commercially available application without platform and positioning device. Thus, in this operational state, the CT table advantageously stands still from the point of view of the outside observer, while the gantry appears to be moving over the CT table and over a body part of a large animal to be examined. Therefore, the computer tomography apparatus allows a stationary large standing animal to not give up its position on the supporting surface during a CT scan and to thus remain stationary relative to the CT device. All movements necessary for the CT scan are performed by the computer tomography apparatus.

Thus, during a CT scan, a large animal will be stationary, standing on solid ground. Advantageously, a large animal and, in particular, the body part of the large animal to be examined, will not move during the CT scan in such a case. Thus, a CT scan can be performed in a particularly reliable manner on a stationary, standing large animal, without the large animal having to be anesthetized in any particular manner and without the large animal being subjected to additional stress.

In the following, preferred embodiments of the computer tomography apparatus pursuant to the invention will be described.

Preferably, during a CT scan, the CT table and the platform are moved in opposite directions at, in terms of absolute values, the same speed. As a result, from the point of view of an outside observer, the movement of the CT table moving into the gantry is compensated by the movement of the platform in the opposite direction. Thus, from the point of view of the outside observer, the CT table is standing still, while the gantry appears to be moving over the CT table. In other words, the CT table and the platform, in particular, move in such a way that, for an outside observer and, in particular, for a large animal standing on the supporting surface, the movement of the CT table relative to the gantry and the platform is compensated by a relative movement of the platform with respect to the supporting surface in the opposite direction. Thus, from the point of view of an outside observer, the CT table is standing still, while, to the outside observer, it looks as if the gantry, which is immovably mounted on the platform, is moving over the CT table and, in particular, over a body part of a large animal to be examined.

In a particularly preferred embodiment, the computer tomography apparatus comprises, in addition, a lifting device. The lifting device is designed to raise or lower the platform relative to the supporting surface for a large animal. Thus, by means of the lifting device and the positioning device, the CT device mounted on the platform can, relative to the supporting surface, be both vertically raised and lowered, and horizontally positioned.

Preferably, a lifting device makes it possible to examine several body parts of a large animal at different heights one after the other, without the large animal having to change its position on the supporting surface significantly. For example, the head, the neck and the forelegs of a large animal can be examined one after the other. The lifting device is preferably designed to raise and lower the CT device in a height range from one to two meters, so that for example the shoulder height of a horse falls within the lifting range of the CT device. Preferably, a large animal can remain stationary, standing on the solid ground in front of the computer tomography apparatus. Thus, in a particularly preferable embodiment, no lifting platform for lifting a large animal to a height required for the CT scan is necessary.

All the movements required for the performance of a CT scan of one body part of a large animal or of several body parts one after the other are solely made by the computer tomography apparatus.

Preferably, the positioning device comprises a rail system arranged on a base plate. The platform having the mounted CT device is preferably arranged on the rail system so that the base plate and the platform are connected via the rail system and can be moved relative to each other. Preferably, the base plate has the same length and width as the platform.

The space required for installing the computer tomography apparatus does not become larger due to the base plate. The base plate may also be designed not as a complete surface, but as a frame. The base plate is designed to carry the weight of the platform and the CT device mounted thereon. The rail system makes it possible to move the base plate and the platform relative to each other in a defined direction with relatively little friction.

Preferably, the positioning device comprises a positioning motor designed to provide a positioning drive for positioning the platform relative to the supporting surface of a large animal. Preferably, the positioning speed of the platform may be up to 14 cm per second. Thus, the positioning motor may be relatively powerful. The positioning motor is preferably an electric motor. The positioning motor is, in particular, designed to provide an output that is sufficient for moving the platform and the base plate—which are connected to each other via the rail system—against each other.

In one embodiment, the positioning device comprises a threaded spindle and a counter thread that is movably mounted on the threaded spindle. Preferably, the positioning motor for driving the threaded spindle is connected to the threaded spindle for example via a belt, and the counter thread is arranged on the platform so that, during the operation of the positioning motor, a rotation of the threaded spindle is converted into a translatory positioning of the platform relative to the supporting surface. Due to the threaded spindle and the counter thread mounted thereon in a movable, yet not rotatable, manner, a rotary motion of the positioning motor that drives the threaded spindle can be converted into a relative positioning movement of the counter thread and therefore of the platform with respect to the threaded spindle. It is therefore a spindle drive.

Preferably, the CT device comprises a CT motor for the motor-driven retraction of the CT table into the gantry.

In one embodiment, the CT device comprises a CT drive, in particular with a CT motor, for the motor-driven retraction of the CT table into the gantry and the positioning device comprises a positioning motor. In this embodiment, the positioning drive and the CT drive are preferably mechanically coupled to each other by means of a coupling.

In one embodiment, the coupling is designed such that a CT drive is picked up directly by a mechanical coupling and transmitted to the positioning drive. A mechanical coupling may, for example, be realized by means of a spindle, via which the CT drive and the positioning drive are connected to each other.

In one embodiment, the positioning drive and the CT drive are coupled to each other in such a way that, during operation, the CT table and the platform move at, in terms of absolute values, the same speed in opposite directions. Preferably, the CT table moves into the opening in the gantry, while the platform is moved into the opposite direction. Thus, both movements are preferably performed simultaneously. Due to the fact that, during a CT scan, the CT table and the platform move at, in terms of absolute values, the same speed in opposite directions, the movement of the CT table is, from the point of view of an outside observer, compensated by the movement of the platform so that, from the point of view of the outside observer, the CT table remains stationary during a CT scan.

In one embodiment, the coupling of the CT drive and the positioning drive is designed such that a start signal is picked up at the CT motor and transmitted to the positioning motor. In that case, the platform is preferably moved by the positioning motor—due to the received start signal—in a direction that is opposite to the direction in which the CT table moves into the opening in the annular gantry.

For example, a number of various speeds may preferably be programmed into a control device of the positioning motor. Thus, a CT protocol during which the CT table is retracted into the gantry in accordance with one of the programmed speeds of the positioning motor at that speed can be chosen for a CT scan. Then, the start signal of the CT motor can be picked up and be transmitted to the positioning motor, so that the CT table and the platform move essentially simultaneously, at, in terms of absolute values, the same speed in opposite directions. Thus, from the point of view of an outside observer, the CT table is standing still, while, to the outside observer, the gantry appears to be moving over the CT table.

In one embodiment, the coupling of the CT drive and the positioning drive is designed such that the speed and/or the position of the CT table and/or of the platform is measured by means of a corresponding speed or position sensor. A speed signal and/or a position signal, which respectively represents a measured speed or position, can then be transmitted as a variable to the CT motor and/or the positioning motor and be used for adjusting the CT motor and/or the positioning motor. In that case, the speed and/or position are variables by means of which the CT motor and/or the positioning motor can be manipulated in a targeted manner, for example via the rotational speed as the controlled variable. The variables are, in particular, used in order to adjust the CT motor and/or the positioning motor in such a way that the CT table and the platform move at, in terms of absolute values, the same speed in opposite directions. This, too, makes it possible to synchronize the movements of the CT table and the platform in such a way that, from the point of view of an outside observer, the CT table is standing still, while the gantry appears to be moving over the CT table.

In one embodiment, in which the platform with the CT device is arranged on a base plate, the lifting device comprises a plurality of threaded spindles. The threaded spindles of the lifting device are preferably, with respect to the base plate, arranged vertically in the direction of the platform on the side of the base plate and respectively connected to the base plate via a movably mounted counter thread. Thus, preferably, counter threads which are respectively movably mounted on a threaded spindle are respectively attached to the base plate. When the threaded spindles are driven, the base plate and the platform with the CT device arranged on the base plate can be raised or lowered.

Preferably, four columns are provided, with one threaded spindle being arranged in each one of them. The four columns are preferably arranged on the side of the base plate such that, with respect to the base plate, the threaded spindles in the columns extend respectively perpendicularly in the direction of the platform. The columns contribute to the stability of the lifting device and protect the threaded spindles of the lifting device from external influences, such as dirt.

In one embodiment, the lifting device comprises at least one lifting motor, that is connected to one of the threaded spindles in order to drive at least one of the plurality of threaded spindles of the lifting device, and designed to provide a lifting drive for raising or lowering the platform relative to the supporting surface for a large animal. The lifting motor is preferably designed to provide an output that is sufficient for driving a threaded spindle and for thus raising or lowering the base plate and the platform with the CT device arranged thereon. The lifting motor as well may be connected to one or several threaded spindles via belts. The lifting motor is preferably an electric motor.

Preferably, at least two of the counter threads of the lifting device are mechanically connected to each other by means of a synchronization device. A synchronization device may, for example, be realized by means of a connecting element that mechanically couples two counter threads to each other. A connecting element may, for example, be a metal rod or a concrete element. Thus, when a threaded spindle is driven and the counter thread movably mounted on it is moved along the threaded spindle, another counter thread, that is connected to the counter thread via a synchronization device, is moved synchronously to the counter thread of the driven threaded spindle. It can also be advantageous to mechanically connect more than two counter threads with each other via a synchronization device.

In one embodiment, in which the platform with the CT device is arranged on a base plate, the lifting device preferably comprises at least one hydraulic pressure cylinder. The pressure cylinder is preferably arranged in such a way with respect to the base plate that the base plate can be raised or lowered relative to the supporting surface through the pressurization of the pressure cylinder.

In a preferred embodiment, the computer tomography apparatus comprises an examination stand. Preferably, the examination stand comprises a holding device and a tray held by the holding device onto which a body part of a large animal can be placed. Preferably, the examination stand is arranged such that at least the tray will not move when the platform is positioned by the positioning device. Preferably, the tray is designed such that it can be adjusted in height with respect to the CT device. It is conceivable that the tray may be attached to the holding device such that the tray can be removed from the holding device and be re-attached to the holding device at a different height. The tray may, for example, be attached to the holding device by means of a screw connection, and the holding device may have holes along its height for attaching the tray by means of the screw connection. Thus, the height of the tray with respect to a large animal to be examined can preferably be adapted to the CT device in accordance with the height of the animal. Preferably, the tray is arranged in such a way and adjusted to such a height that, through the movement of the platform with the CT device, the tray can be moved into the opening in the annular gantry, in particular so far that the tray reaches through the opening in the annular gantry. Thus, the gantry can move over the tray so that, during a CT scan, at least a partial area of the tray is located inside the opening in the annular gantry.

Preferably, the tray, and in particular the partial areas of the tray that can potentially be located inside the gantry during a CT scan, are made of a material that is transparent to X-rays. Likewise, a fixing element, for example a strap, made of a material transparent to X-rays is preferably used for holding the body part to be examined in place on the CT table or the tray.

If a computer tomography apparatus comprises a base plate on which the platform having the mounted CT device is arranged, the holding device is preferably attached to the base plate so that the holding device and the tray move along with the base plate, when the base plate is raised or lowered relative to the supporting surface by the lifting device.

Due to the fact that the holding device is mounted to the base plate, the holding device with the tray can be adjusted in height together with the base plate. Thus, when the base plate is raised or lowered by means of the lifting device, the holding device with the tray is raised or lowered accordingly along with the base plate. Thus, the tray can be adapted to the height of a large animal to be examined and, in particular, to the height of a body part to be examined, for example to the height of a horse head or neck.

Preferably, the holding device is designed such that it ensures that the CT device is protected against any action on the part of the large animal to be examined. For example, an adjustable strap may be attached to the holding device in such a way that the way forward, into the direction of the CT device, is blocked for a large animal, in order to thus protect the CT device for example from being kicked.

Preferably, the holding device is arranged on the base plate in such a way that it can be easily removed, for example through the loosening of a number of screws or other fastening means. Preferably, a holding device can thus be removed for a CT scan of a large animal under general anesthesia and an operating table can be positioned directly adjacent to the gantry.

Since, during a CT scan, the CT table remains stationary relative to the supporting surface for a large animal, the tray can also be connected to the CT table on the side of the tray facing the CT table. Thus, the stability of the tray can be increased. Accordingly, in one embodiment, a computer tomography apparatus comprises a holding device with a tray, whereby the tray is connected to the CT table on the side facing the CT table. Thus, the tray can be moved into the opening in the annular gantry via the positioning of the platform.

In one embodiment, the gantry of a commercially available CT device has been rotated by 180° with respect to the CT table. In that case, the CT tubes and the detector eccentrically arranged in the gantry are preferably closer to the large animal to be examined, since, for a CT scan, the large animal is on the side of the gantry opposite the CT table and, therefore, on the side where originally no patient to be examined is located during a CT scan.

In one embodiment, the CT table is uncoupled, i.e the CT motor runs freely. In that case, the CT table can advantageously be moved freely and also be fixed in any position as a supporting surface for a body part of a large animal.

In one embodiment, the tray is mechanically connected to the CT table on the side facing the CT table, and the CT table is uncoupled and therefore freely movable with respect to the rest of the CT device, so that, when the CT device mounted on the platform is positioned by the positioning device along with the platform, during a relative movement with respect to the gantry, the CT table connected to the tray remains stationary relative to the supporting surface, due to the mechanical connection to the tray. Thus, when the platform is positioned by means of the positioning device, the entire CT device mounted on the platform moves along with the platform. Thus, the gantry appears to be moving relative to the supporting surface for the large animal. The CT table is connected to the tray, whereby the tray is arranged such that it does not move along with the platform when the platform is positioned. Thus, the tray holds the CT table in a fixed position. This is possible because the CT table is uncoupled and therefore freely movable with respect to the rest of the CT device. For an outside observer it will look as if the table is standing still while the platform is being positioned and the gantry appears to be moving over the CT table.

Preferably, the gantry has a laser that is arranged in the gantry and designed such that, during a CT scan, it makes the examined area visible by means of emitted laser light.

In one embodiment the computer tomography apparatus comprises a radiation protection device, in particular lead coats that are respectively installed in front of and behind the gantry. In that case, examination personnel can advantageously help during a CT scan of a large animal and, for example, standing next to a horse, hold a horse leg in place, or standing in front of the horse, hold its head in place without being exposed to a radiation dose that is harmful to health.

The above described computer tomography apparatuses can also be used within a computer tomography scan arrangement, whereby the computer tomography scan arrangement comprises a computer tomography apparatus, a supporting surface for a large animal and a pit in the floor. The computer tomography apparatus is arranged in the pit in the floor such that at least a part of the computer tomography apparatus is located at a lower level compared to the supporting surface. The supporting surface is located outside the pit in the floor, adjacent to the side wall of the pit in the floor that is closest to the gantry of the computer tomography apparatus.

Preferably, the pit in the floor is designed to be so deep with respect to the supporting surface that, when the CT device is completely lowered by means of a lifting device, the CT table of the CT device is level with the supporting surface. In this state, it is advantageously possible to position a head of a horse above the gantry. In that case, a foreleg of the horse can be placed on a tray of an examination stand or the CT table such that it is leaning forward diagonally, so that, during the CT scan, the gantry appears to be moving over the foreleg relative to the supporting surface for the horse. Accordingly, a horse's hind leg can be placed on a tray or the CT table such that it is leaning backwards diagonally. Since, preferably, the computer tomography apparatus is embedded to 50% in the pit in the floor, it is possible to perform CT scans of the limbs of a standing large animal in a particularly advantageous manner.

In that case, the CT device can preferably be raised up to two meters by means of a lifting device so that, when the CT device is in its raised state, it is also possible to perform a CT scan of the head and the neck of a large animal. Thus, the computer tomography scan arrangement makes it possible to examine both the limbs and the head or neck of a stationary, standing large animal in a particularly advantageous manner. In particular, the computer tomography scan arrangement makes it possible to perform such an examination in a particularly advantageous manner by means of a commercially available CT device.

When the supporting surface for a large animal is located on a pedestal, an effect similar to the one achieved through the arrangement of a computer tomography apparatus in a pit in the floor can be achieved. In that case, the pedestal is arranged with respect to the computer tomography apparatus in such a way that the horse will stand at an identical position, albeit elevated. Due to the pedestal, the supporting surface is preferably at the height of the CT table when the CT device is completely lowered by means of the lifting device. With this arrangement, the limbs of a large animal can be examined by means of the computer tomography apparatus in a particularly advantageous manner. By means of a lifting device, the CT device can then be raised in a lifting range of up to two meters, so that it is relatively easy to examine the head or the neck of the stationary large animal standing on the pedestal by means of the computer tomography apparatus.

With regard to the method, the object of the invention mentioned at the beginning is achieved by means of a method of examining a body part of a large animal by means of a computer tomography apparatus. The computer tomography apparatus comprises a computer tomography (CT) device and a platform on which the CT device is mounted. The CT device has an annular gantry and a CT table to accommodate a body part of a large animal to be examined. The CT table and the gantry are movably connected to each other in such a way that the CT table can be moved into a central opening in the annular gantry.

The method pursuant to the invention comprises the following steps:

-   -   positioning a large animal on a supporting surface,     -   placing a body part to be examined onto the CT table or a tray         of the CT device,     -   positioning the platform with the CT device relative to the         supporting surface,         whereby the positioning of the platform in an operational state         is designed such that during a relative movement with respect to         the gantry the CT table or the tray remains stationary relative         to the supporting surface.

One embodiment of the method pursuant to the invention requires that in the operational state the CT table moves into the opening in the annular gantry in a first direction, and that the platform is positioned in a second direction that is opposite to the first direction, whereby the retraction of the CT table and the positioning of the platform are respectively performed at, in terms of absolute values, the same speed, so that the CT table remains stationary relative to the supporting surface.

Thus, the retraction of the CT table and the positioning of the platform are preferably performed as movements in opposite directions at, in terms of absolute values, respectively the same speed so that the CT table remains stationary relative to a supporting surface for a large animal.

Preferably, the method further comprises

-   -   raising or lowering the platform relative to a supporting         surface for a large animal.

In the following, the invention shall be explained in more detail based on an exemplary embodiment with reference to the figures. The figures show the following:

FIG. 1: a computer tomography apparatus for examining a body part of a large animal;

FIG. 2: a lateral view of a computer tomography scan arrangement comprising a computer tomography apparatus arranged in a pit in the floor;

FIG. 3: a computer tomography apparatus with a holding device and a tray;

FIG. 4: a computer tomography apparatus for examining a body part of a large animal.

FIG. 1 shows a computer tomography apparatus 100 for examining a body part of a large animal.

The computer tomography apparatus 100 comprises a CT device 102 that comprises an annular gantry 104 and a CT table 106. The gantry 104 is designed as an annular tunnel in which a CT tube and, opposite from the CT tube, a detector (both elements are not shown) are arranged. In its center, the annular gantry 104 has an opening 108. The CT table 106 and the gantry 104 are movably connected to each other in such a way that the CT table 106 can be moved into the opening 108 in the annular gantry 104. A CT device 102 as shown in FIG. 1 is generally freely commercially available.

The computer tomography apparatus 100 further comprises a platform 110 on which the CT device 102 is mounted. The platform 110 is arranged on a base plate 112, whereby a rail system 114 is located between the base plate 112 and the platform 110. The rail system 114 makes it possible to move the base plate 112 and the platform 110 back and forth in the directions in which the CT table 106 can be moved as well with relatively little friction between each other. The rail system 114 is an element of a positioning device, which further comprises a positioning motor (not shown) and a threaded spindle (not shown) that can be driven by the positioning motor, whereby a counter thread (not shown) is movably mounted on the threaded spindle. The counter thread is permanently connected to the platform 110 so that during the operation of the positioning motor a rotation of the threaded spindle is converted into a translatory positioning of the platform 110 relative to a supporting surface for a large animal. The supporting surface is located on the side 116 of the gantry 104 opposite the CT table 106. Thus, the supporting surface, on which a stationary large animal is standing during a CT scan, is located outside the computer tomography apparatus 100. Thus, the positioning device makes it possible to position the platform 110 having the mounted CT device 104 relative to a supporting surface for a large animal.

The computer tomography apparatus 100 has at least one operational state in which the platform 110 is positioned in such a way that during a relative movement with respect to the gantry the CT table 106 remains stationary relative to the supporting surface. For example, the CT table 106 and the platform 104, in particular, can, in said operational state, move in such a way that, for an outside observer and, in particular, for a large animal standing on the supporting surface, the movement of the CT table 106 is compensated by a movement of the platform 110 in the opposite direction. Thus, to the outside observer it looks as if the gantry is moving over the CT table, while the CT table is standing still.

In this operational state, the CT table 106 would, as intended, move into the opening 108 in the gantry 104 and therefore actually move towards a large animal standing behind the gantry. However, the platform 110 with the CT device 102 moves at, in terms of absolute values, the same speed away from the supporting surface for the large animal. As a result, a body part that has been placed on the CT table remains in a stationary position relative to the supporting surface, while the gantry 104 appears to be moving over the body part. Thus, from the point of view of an outside observer, the CT table 106 appears to be standing still in this operational state, while the gantry 104 appears to be moving over the CT table 106 onto which a body part of a large animal to be examined may be placed.

In the shown embodiment, the CT device 102 comprises a CT motor (not shown), that is designed to allow a motor-driven positioning of the CT table 106. In the shown embodiment, the CT motor and the positioning motor are coupled in such a way that a start signal is picked up at the CT motor and transmitted to the positioning motor as soon as the CT table driven by the CT motor starts moving in the direction of the opening 108 in the gantry 104. A number of predefined speeds are programmed into the positioning motor or into a control device of the positioning motor, and one of the programmed speeds is selected for a CT scan. Accordingly, a CT protocol is chosen for a CT scan in such a way that, during a CT scan, the CT table moves at the selected speed of the positioning motor. Thus, the CT motor and the positioning motor are implemented independently of one another. However, the speeds of the two motors are synchronized via the start signal. In that case, the platform 110 is moved by the positioning motor—due to the received start signal—essentially simultaneously in a direction that is opposite to the direction in which the CT table 106 moves into the opening 108 in the annular gantry 104 at, in terms of absolute value, the same speed. From the point of view of an outside observer, the CT table 106 appears to be standing still in that case, while the gantry 104 appears to be moving over the CT table 106 and, in particular, over a body part of a large animal to be examined.

As an alternative to a coupling realized through the start signal being picked up, the coupling between the CT motor and the positioning motor can be designed such that the CT drive and the positioning drive are mechanically connected to each other. In an embodiment that is not shown, the CT drive and the positioning drive are connected to each other via a spindle. In that case, the movement is picked up directly at the CT table and mechanically transmitted to the positioning drive via a spindle. As a result, the movement of the platform is directly coupled to the movement of the CT table. This makes it possible to advantageously improve a synchronization of the movements of the CT table and of the platform further. If, for example, the CT table is moved manually or via the control console, the platform will move at, in terms of absolute values, the same speed and, in particular, in a direction that is opposite to the direction in which the CT table moves into the gantry.

Thus, from the point of view of the outside observer, the gantry appears to be moving over the stationary CT table.

In another embodiment that is not shown, the coupling of the CT drive and the positioning drive is designed such that the speed and/or the position of the CT table and/or of the platform is measured by means of a corresponding speed or position sensor. A speed signal and/or a position signal, which respectively represents a measured speed or position, can then be transmitted to the CT motor and/or the positioning motor and be used for adjusting the CT motor and/or the positioning motor in such a way that the CT table and the platform move at, in terms of absolute values, the same speed in opposite directions.

Four columns 118 are arranged on the side of the base plate 112; a threaded spindle 120 is arranged in each one of these columns 118. The threaded spindles 120 are elements of a lifting device and are, with respect to the base plate 112, arranged perpendicularly in the direction of the platform 110 on the side of the base plate 112. Each one of the treaded spindles 120 is respectively connected to the base plate 112 via a movably mounted counter tread 122. Thus, the counter threads 122 are permanently connected to the base plate 112 and respectively movably mounted on a threaded spindle 120. When the threaded spindles 120 of the lifting device are driven, the base plate 112 and the platform 110 with the CT device 102 arranged on the base plate can be raised or lowered. In order to drive the threaded spindles 120 of the lifting device, two of the threaded spindles 120 are respectively connected to a lifting motor 124.

The counter threads 122 of the lifting device that are arranged in columns 118 on the same long side of the base plate are mechanically connected to each other via a synchronization device 126. The synchronization devices 126 are designed as continuous connecting elements and respectively couple two counter threads of a long side of the base plate mechanically to each other. The connecting elements 126 are also connected to the base plate 112 so that the connection between the counter threads 122 and the base plate 112 is further supported.

When the threaded spindles 120 of the lifting device, which can be driven directly by the lifting motor, are driven during the operation of the motor and when the counter threads 122 movably mounted on the threaded spindles 120 respectively move along the threaded spindles 120, the synchronization devices 126 with the additional counter threads 118 connected to the counter threads 118 move synchronously to the counter threads 118 of the driven threaded spindles 120. As a result, the base plate 112 can be raised or lowered evenly.

In an embodiment that is not shown, the lifting device comprises in addition or as an alternative to a spindle drive at least one hydraulic pressure cylinder. In such an embodiment, a pressure cylinder is arranged in such a way with respect to the base plate that the base plate can be raised or lowered relative to a supporting surface through the pressurization of the pressure cylinder.

FIG. 2 shows a lateral view of a computer tomography scan arrangement 200 comprising a computer tomography apparatus 202 arranged in a pit in the floor, a pit in the floor 204 and a supporting surface for a large animal 206.

The computer tomography apparatus 202 is designed analogously to the computer tomography apparatus described in connection with FIG. 1 and comprises in particular a CT device 208 with a gantry 210 and a CT table 212 that can be moved into an opening in the annular gantry 208 by means of a CT motor. The CT device 208 is mounted on a platform 214, which is arranged on a base plate 216. By means of a positioning device (not shown), the platform with the CT device 208 can be moved back and forth relative to the supporting surface 206 in the direction in which the CT table 212 can be moved as well. The base plate 216 can be raised and lowered by means of a lifting device 218 so that the CT device 208 mounted on the platform 214 can, by means of the lifting device 218 and the positioning device—relative to the supporting surface 206—be both vertically raised and lowered, and horizontally positioned.

As shown by FIG. 2, the supporting surface 206 is located outside the pit in the floor 204, namely adjacent to the side wall 220 of the pit in the floor 206 that is closest to the gantry 210 of the computer tomography apparatus 202. Preferably, the pit in the floor 204 has a depth that is dimensioned such that, when the CT device 202 is, as shown in FIG. 2, completely lowered by means of the lifting device 218, the CT table 212 of the CT device 208 is level with the supporting surface 206.

In the illustrated exemplary embodiment, the head of a large animal can be positioned above the gantry such that the torso of the large animal is located directly in front of the gantry. In this completely lowered state, a foreleg of the large animal, for example, can be placed on the CT table 212 such that the leg is leaning forward diagonally, so that, during a CT scan, the gantry 210 appears to be moving relative to the supporting surface 206 for the large animal over the foreleg. Accordingly, a hind leg of a large animal can be placed on the CT table 212 such that the leg is leaning diagonally backwards.

The pit in the floor 204 has a lateral extension that makes it possible to position the platform 214 relative to the base plate 216 by means of a positioning device, without the platform hitting the side walls of the pit in the floor 204. Thus, especially on the corresponding sides of the computer tomography apparatus 202, the distance 222 between the [wall of] pit in the floor 204 and the computer tomography apparatus 202 is relatively large. On the two long sides of the computer tomography apparatus 202, along which the platform 214 is not moved relative to the base plate 216 during a CT scan, the side walls of the pit in the floor 204 may be located at a relatively small distance from the computer tomography apparatus 202.

By means of the lifting device 218, the CT device 210 can be raised up to two meters. In an embodiment that is not shown, a CT device can be raised more than two meters, for example up to three meters. When the CT device is in the raised state, a CT scan of the head or neck of a large animal, for example, can be performed. Thus, the illustrated computer tomography scan arrangement 200 makes it possible to examine both the limbs and the head or neck of a stationary, standing large animal. The illustrated computer tomography scan arrangement 200 makes it in particular possible to use the same commercially available CT device 202 for examining the head, the neck and the forelegs of a stationary, standing large animal one after the other, without the large animal having to change or give up its stationary position on the supporting surface 206.

FIG. 3 shows two views of one computer tomography apparatus 300 comprising an examination stand which in turn comprises a holding device 302 and a tray 304.

The tray 304 is attached to the holding device 302 and designed such that a body part of a large animal—in this case, a horse—can be placed on the tray 304. The holding device is attached to a base plate 306 so that the holding device 302 and the tray 304 do not move along when a platform 308 is positioned by means of a positioning device. However, when the base plate 306 is raised or lowered by means of a lifting device, the holding device 302 and the tray 304 move along with the base plate 306, so that the tray 304 can be adjusted to a specific height with respect to the large animal to be examined. Thus, the tray 304 can be adapted to the height of a large animal to be examined and, in particular, to the height of a body part to be examined, for example to the height of a horse head or neck.

However, with respect to the CT device, the tray 304 is arranged at such a height that, through the movement of the platform 308 with the CT device, the tray 304 can be moved into the opening 310 in the annular gantry 312, in particular so far that the tray 304 reaches through the opening 310 in the annular gantry 312. Thus, from the point of view of the outside observer, the gantry 312 appears to be moving over the tray 304 during a scan.

On the side facing the supporting surface for a large animal, a metal structure 314 is attached to the computer tomography apparatus 300. The metal structure 314 serves as protection for the CT device from any actions on the part of the large animal, for example as protection against kicks against the CT device.

In the shown embodiment of a computer tomography apparatus 300 with an examination stand, the tray may be mechanically connected to the CT table on the side facing the CT table. When the CT table is uncoupled and therefore freely movable with respect to the rest of the CT device, the CT table is not positioned along with the platform and the rest of the CT device, when the platform is positioned by means of the positioning device. In that case, the CT table is, from the point of view of the outside observer, held in a fixed position due to the mechanical connection to the tray. When the CT device is positioned along with the platform by means of the positioning device, due to the mechanical connection to the tray, the CT table appears to remain stationary relative to the supporting surface, while the gantry appears to be moving over the CT table relative to the supporting surface.

FIG. 4 shows a computer tomography apparatus 15 for examining a body part of a large animal. The computer tomography apparatus 15 comprises a CT device that comprises a gantry 12 and a CT table 11. The CT device is arranged on a base plate 13, that can be vertically raised or lowered by means of a lifting device 16. The gantry 12 is immovably arranged on the base plate 13. The CT table 16 is horizontally movably arranged on the base plate 13 and can move horizontally relative to the gantry and/or the base plate. The base plate 13 and the lifting device 16 are arranged on a platform 18. The platform 18 is arranged on solid ground 14, for example in a pit in the floor, and can be positioned horizontally with respect to the solid ground 14 by means of a positioning device 20.

LIST OF REFERENCE NUMBERS

-   11 CT table -   12 gantry -   13 base plate -   14 ground -   15 computer tomography apparatus -   16 lifting device -   18 platform -   20 positioning device -   100 computer tomography apparatus -   102 CT device -   104 gantry -   106 CT table -   108 opening -   110 platform -   112 base plate -   114 rail system -   116 side of the gantry opposite the CT table -   118 columns of the lifting device -   120 threaded spindles of the lifting device -   122 counter threads of the lifting device -   124 lifting motor -   126 synchronization device -   200 computer tomography scan arrangement -   202 computer tomography apparatus -   204 pit in the floor -   206 supporting surface for a large animal -   208 CT device -   210 gantry -   212 CT table -   214 platform -   216 base plate -   218 lifting device -   220 side wall -   222 distance between the base plate and the side wall -   300 computer tomography apparatus -   302 holding device -   304 tray -   306 base plate -   308 platform -   310 opening -   312 gantry -   314 metal structure 

The invention claimed is:
 1. A computer tomography apparatus for examining a body part of a large animal, comprising: a computer tomography device with an annular gantry and a CT table to accommodate the body part of the large animal to be examined; and a platform on which the CT device is mounted, whereby the gantry is immovable relative to the platform, whereby, relative to the platform and to the gantry, the CT table is horizontally movably connected to one or both of the gantry and the platform in such a way that the CT table can be moved into an opening in the annular gantry, whereby the computer tomography apparatus comprises a positioning device which is connected to the platform and is configured to horizontally position the platform having the mounted CT device relative to a supporting surface for the large animal, and whereby the positioning device is designed to position the platform with the CT device in at least one operational state in such a way that, during a relative movement of the CT table with respect to the gantry, the CT table remains stationary relative to the supporting surface.
 2. The computer tomography apparatus of claim 1, further comprising a lifting device, whereby the lifting device is designed to vertically raise or lower the platform relative to the supporting surface for the large animal, so that, by means of the lifting device and the positioning device, the CT device mounted on the platform can, relative to the supporting surface, be both vertically raised and lowered and horizontally positioned.
 3. The computer tomography apparatus of claim 1, whereby the positioning device comprises a rail system that is arranged on a base plate, and whereby the platform having the mounted CT device is arranged on the rail system such that the base plate and the platform are relative to each other movably connected to each other via the rail system.
 4. The computer tomography apparatus of claim 1, whereby the positioning device comprises a positioning motor that is designed to provide a positioning drive for positioning the platform relative to the supporting surface for the large animal, and whereby the positioning device comprises a threaded spindle and a counter thread movably mounted on the threaded spindle, whereby, in order to drive the threaded spindle, the positioning motor is connected to the threaded spindle, and the counter thread is arranged on the platform such that, during the operation of the positioning motor, a rotation of the threaded spindle is converted into a translatory positioning of the platform relative to the supporting surface.
 5. The computer tomography apparatus of claim 1, whereby the CT device comprises a CT drive for the motor-driven retraction of the CT table into the gantry, and whereby a positioning drive and the CT drive are mechanically coupled to each other via a coupling, whereby the coupling is designed such that the CT drive is directly picked up and transmitted to the positioning drive.
 6. The computer tomography apparatus of claim 5, whereby the mechanical coupling of the CT drive and the positioning drive is designed such that, during operation, the CT table and the platform move at, in terms of absolute value, the same speed in opposite directions.
 7. The computer tomography apparatus of claim 2, whereby the platform with the CT device is arranged on a base plate and the lifting device comprises a plurality of threaded spindles, that with respect to the base plate, are perpendicularly arranged on the side of the base plate in the direction of the platform, and that are respectively connected to the base plate via a movably mounted counter thread.
 8. The computer tomography apparatus of claim 7, whereby the lifting device comprises at least one lifting motor, that is connected to one of the threaded spindles in order to drive at least one of the plurality of threaded spindles of the lifting device, and designed to provide a lifting drive for raising or lowering the platform relative to supporting surface for a large animal.
 9. The computer tomography apparatus of claim 2, whereby the platform with the CT device is arranged on a base plate and the lifting device comprises at least one hydraulic pressure cylinder, that, with respect to the base plate, is arranged in such a way that the base plate can be raised or lowered relative to the supporting surface through the pressurization of the pressure cylinder.
 10. The computer tomography apparatus of claim 1, further comprising an examination stand, whereby the examination stand comprises a holding device and a tray held by the holding device, whereby the examination stand is arranged such that the tray is not moved along when the platform is positioned by means of the positioning device.
 11. The computer tomography apparatus of claim 10, further comprising a base plate on which the platform having the mounted CT device is arranged, whereby the holding device is attached to the base plate so that the holding device and the tray move along with base plate, when the base plate is raised or lowered relative to the supporting surface by the lifting device.
 12. The computer tomography apparatus of claim 11, whereby the tray is mechanically connected to the CT table on a side facing the CT table, and whereby the CT table is uncoupled and therefore freely movable with respect to the rest of the CT device, so that, when the CT device mounted on the platform is positioned by the positioning device along with the platform, during a relative movement with respect to the gantry, the CT table connected to the tray remains stationary relative to the supporting surface, due to the mechanical connection to the tray.
 13. A computer tomography scan arrangement comprising a computer tomography apparatus of claim 1, whereby the computer tomography apparatus is arranged in a pit in a floor such that at least a part of the computer tomography apparatus is located at a, compared to the supporting surface, lower level, and whereby the supporting surface is located outside the pit in the floor adjacent to the side wall of the pit in the floor that is closest to the gantry of the computer tomography apparatus.
 14. A method of examining a body part of a large animal with a computer tomography apparatus comprising: a computer tomography device with an annular gantry and a CT table to accommodate the body part of the large animal to be examined; and a platform on which the CT device is mounted, whereby the gantry is immovable relative to the platform, and whereby, relative to the platform and to the gantry, the CT table is horizontally movably connected to one or both of the gantry and the platform in such a way that the CT table can be moved into an opening in the annular gantry, whereby the method comprises the steps of: positioning a large animal on a supporting surface; placing the body part to be examined onto the CT table or a tray of the CT device; and positioning the platform with the CT device relative to the supporting surface, whereby the positioning device is designed to position the platform with the CT device in at least one operational state in such a way that during a relative movement of the CT table with respect to the gantry, the CT table remains stationary relative to the supporting surface.
 15. The method of claim 14, whereby in the operational state the CT table moves relative to the platform into the opening in the annular gantry in a first direction, and the platform is positioned relative to the supporting surface in a second direction that is opposite to the first direction, whereby the retraction of the CT table and the positioning of the platform are respectively performed at, in terms of absolute values, the same speed, so that the CT table remains stationary relative to the supporting surface.
 16. The computer tomography apparatus of claim 1, wherein the at least one operational state is such that, during a relative movement of the CT table with respect to the gantry, the CT table is configured to enter the opening of the annular gantry relative to the platform via movement in a first direction, and the platform is configured to displace relative to the supporting surface via movement in a second direction opposite the first direction.
 17. The computer tomography apparatus of claim 16, wherein movement of the CT table in the first direction, and movement of the platform in the second direction are each performed at equal speeds so the CT table remains stationary relative to the supporting surface.
 18. The computer tomography apparatus of claim 1, whereby the at least one operational state includes scanning by the CT device.
 19. The computer tomography apparatus of claim 18, whereby, during scanning, the CT table remains stationary relative to the supporting surface while displacing relative to the gantry and the platform. 